Greases thickened with fibrous asbestos which fibers are coated with aliphatic esters of n-acyl(aliphatic)aminobenzoic acid

ABSTRACT

Lubricating greases thickened with fibrous asbestos which fibers are coated with aliphatic (up to 30 carbon atoms) esters of Nacyl (aliphatic up to 30 carbon atoms) aminobenzoic acid.

United States 5i Cross et a1.

GREASES THICKENED WITH FIBROUS ASBESTOS WHICH FIBERS ARE COATED WITH ALIPHATIC ESTERS OF N-ACYL (ALIPHATIC) AMINOBENZOIC ACID Inventors: Edward A. (Iross, Houston, Tex.;

Richard L. Frye, Baton Rouge, La.; Robert T. Daniel, Beaumont; Gordon S. Bright, Nederland, both of Tex.

Assignee: Texaco Inc., New York, N.Y.

Filed: Apr. 30, 1970 Appl. No.2 33,532

U.S. C1 252/13, 252/28, 252/51.5 A Int. Cl. ClOm 5/20, Cl0m 7/34 Field of Search 252/13, 21, 28, 51.5 A,

References Cited UNITED STATES PATENTS 1/1958 Hotten 252/33.6

[ NOV. 20, 1.973

Primary Examiner-Danie1 E. Wyman Assistant Examinerl. Vaughn Att0rneyTh0mas H. Whaley and Carl G. Ries ABSTRACT Lubricating greases thickened with fibrous asbestos which fibers are coated with aliphatic (up to 30 carbon atoms) esters of N-acyl (aliphatic up to 30 carbon atoms) aminobenzoic acid.

6 Claims, N0 Drawings 1 GREASES THICKENED WITH FIBROUS ASBESTOS WHICH FIBERS ARE COATED WITH ALIPHATIC ESTERS OF N-ACYL (ALIPHATIC) AMINOBENZOIC ACID This invention is related to grease compositions thickened with fibrous inorganic materials coated with hydrophobic materials.

More particularly, this invention concerns lubricating oils thickened to grease consistency with inorganic fibres coated with oil-soluble aromatic coating agents.

The use of finely divided fibrous materials such as asbestos or fibrous glass as a filler or thickener in lubricating greases is old in the art. See for example, Manufacture and Application of Lubricating Greases" by C.J. Boner, 1954 edition, pages 757-794, particularly pages 771-773, Lubricating Greases: Their Manufacture and Use," Klemgard, published by Reinhold Publishing Co., pages 725-756 as well as pages 71, 31 1, etc. In addition, the subject is also extensively covered in the patent literature, see for example U.S. Pat. No. 3,010,896 (Odell) and US. Pat. No. 3,424,678 and US. Pat. No. 3,433,743 (Morway et a1).

Unfortunately, the above greases have been less than satisfactory in one or more respects. For example, the greases alluded to by Boner have poor shear stability and have relatively poor stability in the presence of water. The greases disclosed by Odell comprise water soluble surfactants which must be applied in an aqueous media and require separate and lengthy drying and extraction steps to substantially remove the unwanted water in the system. Further, the resultant greases, while relatively satisfactory, are not superior greases. The two Morway, et a] patents require the use ofa particular colloidal size asbestos substrate to be effective.

Recently the applicants have discovered that greases thickened with inorganic fibrous substrates coated with oil-soluble aromatic coating agents overcome the enumerated shortcomings of the prior art. For instance, the novel greases have good shear stability and are stable in the presence of water. In addition, because of their oil-solubility, the coating agents of this invention can be applied under non-aqueous reaction conditions either in situ or preformed and thus obviate tedious and costly dehydration steps in grease manufacture.

In view of the above-recited shortcomings of the prior art, the applicants thickening systems and the greases produced from these systems represent an advance in the art.

It is an object of this invention, among others, to provide novel greases having good shear stability, water resistance and E.P. properties.

It is another object of this invention, among others, to provide novel thickening systems applicable to a wide variety of natural lubricating oils.

A more specific object of this invention is to provide novel coating agents which can be applied to both colloidal and non-colloidal asbestos substrates in a nonaqueous environment.

Additional objects will suggest themselves to those skilled in the art after reading this disclosure.

In practice, a grease is prepared by admixing a major amount of one or more oils of lubricating viscosity and a minor amount of optional adjuvants, with a thickening system comprising a. at least one inorganic fibrous material, and

b. at least one aromatic coating agent under reaction conditions suitable to produce a coating of said aromatic coating agent upon said inorganic fibrous material until a lubricant of grease-like consistency is obtained. If desired, the grease can be subsequently milled to a desired consistency.

In the favored practice, a grease comprising about 55 to 98 weight percent of a mineral oil of lubricating viscosity and about 45 to 2 weight percent with a thickening system containing inorganic fibrous material and aromatic coating agent is prepared by admixing said grease components between about 200 and 400 F. until the desired thickening takes place.

In the most favored practice, a grease having superior shear stability, water-resistance and extreme pressure properties is prepared by admixing at between about 200 and 400 F., about 65 to 96 weight percent of a mineral oil of the naphthenic or paraffinic type with about 35' to 4 weight percent of a thickening system made up of about 25 to 3.5 weight percent of fibrous asbestos and about 10 to 0.5 weight percent of aromatic coating agent, until said grease is prepared.

In the preferred practice a grease product having superior properties of shear stability, water-resistance and extreme pressure properties is prepared by admixing between about 200 F. to 400 F. the following components:

about 68 to 94 weight percent of a paraffinic oil having initial viscosities between about 800 SUS to 2,000 SUS, and about 32 to 6 weight percent of a thickening system comprising about 25.5 to 5.0 weight percent of chrysotile asbestos coated with about 6.5 to 1.0 weight percent of a para substituted aromatic coating agent selected from the structures consisting of:

wherein R is an alkyl radical, containing 12 to 20 carbon atoms, and R is selected from the group consisting of sodium lithium and alkyl radicals containing 1 to 12 carbon atoms, until said grease product is prepared.

In order to supplement the subject disclosure of this invention, the following additional disclosure is described more fully below:

A. Fibrous Inorganic Materials The fibrous materials which are suitable as substrates for the novel coating agents of this invention include a wide variety of naturally occurring materials which are found or can be made in the finely divided state and which, under the conditions of formulation, manufacture or application of the grease, are stable to chemical and thermal attack. Most of the materials will range in length from a few'millimicrons to tens of thousands of millimicrons, and will range in diameter from fractions of a micron up to about 500 or more microns. More commonly, the lengths will range from about 500 millimicrons to 50,000 millimicrons.

A useful group of fibrous inorganic materials which are employed as substrates are the siliceous and carbonaceous materials having the requisite stability and size requirements referred to above. The favored materials are the various mixtures of alkaline earth metal silicates with other metal and metal oxides, as well as fibrous carbon and fibrous graphite.

The favored fibrous materials are the naturally derived silicate mixtures generically referred to as asbestos. They can be of the long fibered or short fibered type, colloidal or non-colloidal. Asbestos is favored as a class since it is a plentiful inexpensive material which is relatively stable to chemical and thermal attack which, when coated with the novel coating agents of this invention, are superior thickening agents for converting lubricating oils to greases. The most commonly known types of fibrous asbestos and their theoretical formulae appear below:

Type of Asbestos Actinolite-Ca(Mg Fe)3(SiO H O Amosite-(Fe Mg)SiO l5 percent H O Anthophyllite-Mg Fe)hd 7SlsO22(OH) Chrysotile- 3Mg0 2SiO 2H O CrocidoliteNa Fe (SiO3)2FeSiO H O The information on asbestos presented above, as well as any other data or description relating to asbestos, unless noted otherwise, is taken from the article by MS. Badollet entitled Asbestos, A Mineral of Unparalleled Properties, which appeared in Transactions of the Canadian Institute of Mining and Metallurgy, Vol. LIV 1951, pages 151-160. As is well documented in the literature, conventional forms of asbestos, particularly asbestos floats, among other forms of asbestos, may be used in greases as long as the particle size falls within the usual size limitations of asbestos fillers. That is, the asbestos may range in length from a few millimicrons to thousands of millimicrons. Similary, diameters may range from less than a millimicron up to 100 millimicrons or more with a more useful range of diameters being within 10 to 75 millimicrons. While asbestos substrates are favored as a class, as is frequently the case, where the class comprises a large group of entities, some members of the class are more desirable or superior for one reason or another than the rest of the class as a whole, and are therefore preferred. In this in stance, the chrysotile form of asbestos is preferred because it is available in an especially high state of purity, substantially free from physical and chemical contaminants, and most important, because when coated with the coating agents of this invention, thicken oils of lubricating viscosity to produce greases having superior properties. Unless otherwise noted, when chrysotile asbestos fibers are referred to in the examples it will fall within the range of properties shown below:

Brightness (GE) 0.70-80 Refractive Index 1.40 1.60

Dispersion in water Completely at pH ranges of about 4-6 Surface Area 45-55 sq. meters/gram Oil Absorption 14-16 cc/lO grams of fibers Water Retention 20-25 grams per gram of water Dry Bulk Density 22.5 lbs/cu. ft.

Fiber Dimensions O.D. 20-30 millimicrons I.D. 6.0 millimicrons Length 2,000 30,000 millimicrons B. Lubricating Oils The lubricating oils employed as the base fluid in this invention may be natural (mineral) synthetic or blends of these oils. The mineral oils used are those of the paraffinic, naphthenic, asphaltic or paraffinic-asphaltic type derived from crude oils by refining procedures including distillation, cracking or polymerization. These oils, like their synthetic counterparts to be described more fully below, will have Saybolt Universal Viscosities in the range from about 75 seconds at 100 F. to about 225 seconds at 210 F.

The synthetic oils will include those of the ester type, the ether type and silicones in the monomeric or poly meric form. The ester type oils are derived from esterifying alcohols, particularly aliphatic alcohols, diols, polyols and the like with organic acids particularly aliphatic mono-and/or dicarboxylic acids. The aliphatic acids ordinarily contain from 3 to 25 carbon atoms and the alcohol co-reactant ordinarily has from 2 to 20 carbon atoms. Illustrative esters are as follows: diisooctyl azelate, di-2-ethylhexyl sebacate, di-2-ethylhexyl adipate, di-Z-ethylhexyl azelate, dilauryl azelate, di-secamyl sebacate, di-2-(2-butoxyethoxy) ethyl alkenyl succinate, the di-n-deconate of 1,4-butanediol, the dilaurate of 1,4-hexanedio1, the dioctanoate of l,5- pentanediol, the dilaurate of tetraethylene gylcol, the trimethyl propane triheptanoate, the dioctenoate of 1,5-pentanediol and the like.

The lubricating base oils preferred for thickening are mineral oils selected from the group consisting of naphthenic oils having viscosities at 100 F. ranging from about 800 SUS to 2,000 SUS and higher. These oils may be derived from blends of oils having lower and higher viscosities. The above oils are preferred as bases for greases, particularly under high pressure conditions because they produce greases particularly resistant to bleeding or separation.

C. Optional Adjuvants The term adjuvant as used throughout this disclosure is used to describe all the materials added to a lubricant to impart or enhance desirable properties or to eliminate or minimize deleterious properties. These materials can be of diverse chemical structure and include oxidation inhibitors, E.P. agents, wear prevention agents, stringiness inhibitors, dropping point improvers and tackiness agents. Illustrative adjuvants are metal oxides, phenyl naphthylamines, mercaptobenzothiazoles, dibenzylfulfides, tricresyl phosphates, chlorinated waxes, fatty soaps, polyalkylene polymers. When adjuvants are employed they seldom total more than 10 percent by weight of the finished grease and are added at the expense of the lubricating oil component.

D. Aromatic Coating Agents This is the generic term used to describe the oilsoluble salts or esters of aromatic carboxylic acids containing one or more amide groups substituted on the aromatic nucleus.

The favored aromatic coating agents are those included within the structures:

H 0 o I-ll-R and -NHR l Q R' doon' and wherein R is an alkyl radical containing to 30 carbon atoms and R is selected from the group consisting of alkali metals and alkyl radicals containing 1 to 12 carbon atoms, and hydrogen. The preferred coating agents are selected from the para-substituted aromatic coating agents consisting of:

and

wherein R is an alkyl radical containing from 12 to 20 carbon atoms and R is selected from the group consisting of lithium, sodium and alkyl containing from 1 to 12 carbon atoms, and hydrogen.

The above para-substituted aromatic coating agents are preferred inasmuch as they produce greases having superior properties compared to the class of coating agents as a whole.

E. Processes for Preparing the lnventive Thickening Systems Two processes are illustrated:

1. In situ 2. Preforming 1. In situ At least two variations are possible in regard to when the coating agent is added. In the first procedure the coating agent is added with the initial charge, while in the second procedure the coating agent is added on the cooling cycle. The following are illustrative of the variations when asbestos, the preferred fibrous substrate is employed.

ln the first procedure, the kettle, fitted with heating and agitation means, is charged with lubricating oil, asbestos and the coating agent, and'the mixture is vigourously agitated while heating between about 200 to about 400 F. to thoroughly disperse the ingredients. After a heating period of about 30 to 60 minutes the bath is cooled to about 180 to 240 F. by removing the heat source and/or by quenching by the additionof lubricating oil. After holding at the reduced temperature for about 30 to 60 minutes, the thickened material is milled through a device such as a colloid mill to the desired consistency.

in the second procedure, the grease kettle is charged with lubricating oil and fibrous substrate and heated between about 200 F. to about 400 F. After heating 30 minutes to 60 minutes, the charge is cooled to between about l80 to 240 F. either by removing the heat source or by quenching the charge with aminor to a major portion of additional lubricating oil. At this.

ther of the two variations described above, is admixed with lubricating oil to be thickened and is heated to about 340 to 405 F. for a period ranging from 5 to 60 minutes. At the end of this time the charge is cooled and brought to the desired constituency.

The in situ process for preparing the greases is preferred inasmuch as it requires less handling and shorter process cycles.

F. Preferred Grease Composition The preferred greases comprise:

a. from about 68 to 94 parts by weight of naphthenic mineral oil having SUS viscosities at 100 F. ranging from about 800 to 3000 SUS,

b. from about 25.5 to 5.0 parts of colloidal chrysotile asbestos and c. from about 6.5 to 1.0 parts by weight of at least one oil-soluble coating agent selected from the parasubstituted aromatic coating agent included within the structures of arid wherein R is an alkyl radical containing from 12 to 20 carbon atoms and R is selected from the group consisting of lithium, sodium, alkyl radicals containing from 1 to 12 carbon atoms and hydrogen.

G. Ratio of Thickening System to Grease and Ratio of Fibrous Material to Coating Agent The amount of coating agent requird is a variable dependent upon a number of factors, primarily the fibrous material and the coating agent employed. Thickening effects are obtained when the amount of coating agent present comprises from about 2.0 to 45 parts by weight per parts by weight of final grease product. However, erratic and marginal results are obtained when either of the two extremes of concentration are employed. On the other hand, consistently good results are obtained within a somewhat more restricted range of about 25.5 to 5.0 parts by weight of coating agent per hundred parts by weight of grease, and this represents the preferred range.

The weight ratio of fibrous inorganic material to coating agent is a variable dependent upon the substrate and coating agent employed. Ordinarily the fibrous inorganic material should be present in reasonable excess over the coating agent, that is varying from 1.25:1 to 15:]. When asbestos is the substrate to be coated, favorable results have been obtained when weight ratio of asbestos to the coating material varies between 1.5:1 to 5:1. Inasmuch as the best results have been found in ratios ranging from 2:1 to 4:1, this weight ratio range is preferred.

'l-l. Ratio of Lubricating Oil to Coated Substrate Generally this ratio is not especially critical. Howi ever, favorable results have been obtained when the lubricating oil to coated substrate is between 3:1 to 15:1. When the favored substrate asbestos is used, the preferred weight ratio of lubricant to coated substrate varies from 5.5:l to 9:1.

In order to describe the inventive concept in the greatest detail, the following illustrative examples are submitted. Unless otherwise indicated, all parts and percentages are by weight rather than volume.

EXAMPLE I MINERAL OIL THICKENED BY ASBESTOS COATED WITH THE SODIUM SALT OF p-(N- Lauroyl) AMINOBENZOIC ACID In this example and in Examples 2 and 3, a non-melt procedure is employed in which the coating agent is coated upon asbestos fiber as the salt is formed.

A 300 parts by weight portion of fibers of chrysotile asbestos, whose properties are described supra* (*See page 6), 250 parts by weight of water and 500 parts by weight of a highly refined paraffinic oil (viscosity at 100 F-l600 SUS Viscosity at 210F-l17.8 SUS, flash point of 560 F.) are charged to a conveniently sized reaction vessel equipped with heating and stirring means, and heated to 200 F. At this time a premixed mixture of 60 parts by weight of p-(N-lauroyl) aminobenzoic acid and 250 parts by weight of water at 200 F. are added to the asbestos oil water mixture. After a 15 minute holding period, a 14.5 parts by weight portion of a 49 percent by weight aqueous caustic solution is added to the heated, stirred mixture to form the sodium salt and the stirred mixture is kept at 220 F. for an additional hour. The batch is then heated to 350 F. until dehydration takes place then cooled to 250 F. At this point an additional 398 parts by weight of the above-described paraffinic oil is added and the batch is cooled to 200 F. and milled at 0.003 inch to produce the finished grease whose properties are shown in the Table I.

EXAMPLE 2.

Synthetic Oil Thickened by Asbestos Coated with the Sodium Salt of p-(N-Octadecoyl) Aminobenzoic Acid.

To a conveniently sized reaction kettle is charged 2 parts by weight of the chrysotile asbestos of Example 1, parts by weight of water and parts by weight of a Z-methylpentanoic pentaerythritol tetraester* (*SEE TABLE II). The mixture is heated to 200 F. and an 0.5

part by weight portion of a p-(N-octadecoyl) aminobenzoic acid is added to the heated mixture and the temperature is held at 200 F. for 20 minutes. At the end of this time a 0.12 parts by weight portion of an aqueous sodium hydroxide solution (49 percent by weight) is added, with stirring, and the mixture is held at 200 F. for an additional hour. At the end of this time the batch is heated to 350 F. to dehydrate and it is held at this temperature for five minutes then cooled at a rate of 1 F. per minute as an additional 6.6 parts by weight of the tetraester is added to the mixture and the mixture is cooled to 200 F. and is milled at 0.003 inch to finish the grease whose properties are shown in Table I.

EXAMPLE 3.

A Synthetic Oil Mixture Thickened by Asbestos Coated with the Sodium Salt of p-(N-Octadecoyl) Aminobenzoic Acid.

To a conveniently sized reaction vessel is charged 2.5 parts by weight of the chrysotile asbestos of Example 1, 5 parts by weight of water and 10 parts by weight of di-2-ethylhexyl azelate. The mixture is heated to 200 F. and 0.5 parts by weight of p-(N-octadecoyl) aminobenzoic acid is added to the stirred heated mixture. After holding at 200 F. for 30 minutes, a 0.12 part by weight portion of a 49 percent by weight aqueous solution of sodium hydroxide is added with stirring and the temperature is held for an additional hour. The batch is dehydrated by heating to 350 F. and maintaining it at this temperature for 20 minutes. At the end of this time a blend of di-Z-ethylhexyl azelate See Table II for physical constants of this oil.) (2.5 parts by weight) and diisooctyl adipate" See Table II for physical constants of this oil.) (4.1 parts by weight) is added with stirring at the rate of 0.1 parts per minute while cooling to 300 F. at rate of 1 F. per minute. When the batch reaches 300 F. it is milled twice at 0.003 inch. See Table I for data.

EXAMPLES 4-7.

Thickening of Mineral Oil using Asbestos Coated with Different Coating Agents.

Example No. Coating agent 4 NaOOCQNHCOCnHn 5 --Ca(0 OCQIEHCOCHHZS) 6 IHB Q NH 101121 7 -cnm1ooc-coNrrcmm1 In all instances a satisfactory grease is obtained.

In these examples the procedure of Example 1 is followed exactly except that the coating agents shown below are substituted for p-(N-octadecoyl) aminobenzoic acid on a weight by weight basis.

EXAMPLES 8-10.

Example No. Fibrous Material 8 Graphite Fiber produced by the procedure described in US. Patent No. 3,107,652 (Ford et al) assigned to Union Carbide Corporation I 9 Fibrous glass described in the Slayter Patent No. 3,113,105 Non-Colloidal asbestos whose properties are described in US. Patent No. 3,409,499 assigned to Union Carbide Corporation In each instance the substitution of the designated fibrous materials for the asbestosutilized in Examples 1-3 produced satisfactory greases.

EXAMPLE 1 l.

Thickening of Synthetic Oil using a Melt Procedure and The Methyl of (N-Octadecoyl) Aminobenzoic Acid as Coating Agent.

A mixture of parts by weight of water, 0.5 parts by weight of methyl (N-octadecoyl) aminobenzoic acid and 0.67 parts by weight of lithium hydroxide are charged to a reaction vessel provided with heating and stirring means. The mixture is heated with stirring to l80200 F. and kept within this temperature range for 1.5 hours. Then parts by weight of the 2- methylpentanoic pentaerythritol tetraester used in Example 2 is added and the stirred batch is heated to 250 F. and is held at that temperature for 1 hour. The batch is then heated to 300 F. and 2.5 parts by weight of the chrysotile asbestos used in Examples 1 to 3 is added and the temperature is raised to 450 F. and is held at this temperature for 28 minutes. At that time the batch is quenched by adding 2.0 parts by weight of additional 2-methylpentanoic pentaerythritol tetraester and is allowed to cool to 300 F. and an additional 3 parts by weight portion of the tetraester is added to bring the batch to an NLGI No. 1 grade consistency after milling at 0.003 inch. A satisfactory grease whose properties are shown in Table I is obtained.

PROPERTIES OF SYNTHETIC OILS Composition, Wt.

Z-methylpentanoic pentaerythritol tetraester 100 di-Z ethylhexyl azelate 100 Di-isooctyl adipate 100 Tests Viscosity, CS, 100 F. 25.12 9.89 Viscosity, CS, 210 F. 3.02 2.79 Viscosity, CS, 250 F. 4.94 Flash, F. 490 420 390 CRC Evaporation, 250 F. 0.19

EXAMPLE 1 2.

Comparison of a Typical Grease Composition of this lnvention with Two Greases containing Uncoated Asbestos and a Grease Thickened with Colloidal Asbestos Coated with a Carboxylic Acid as Disclosed in U.S. Pat. No. 3,433,743.

Using the procedure of Examples 1 to 3, a typical asbestos coated grease of this invention (designated 12a) is prepared and compared to two greases containing uncoated colloidal chrysotile asbestos (designated 12b and 12c respectively) and two different greases thickened with carboxylic acids One grease (12d) utilizes l2-hydroxy stearic acid as the coating agent and is substantially equivalent to Example II of US. Pat. No. 3,433,743, while the second grease l2e) closely approximates Example IV of the patent, except that palmitic acid is substituted for linoleic trimer acid used by the patentee.) as disclosed in US. Pat. No. 3,433,743 (designated as 12d and l2e respectively). As can be seen by the data presented in Table III, the physical properties of applicants grease are superior to both of the two greases thickened with uncoated asbestos and the two greases of the prior art. The results are shown in Table III.

TABLE I Ex. Ex. Ex. Ex.

Composition Wt. l 2 3 10 Asbestos 24.2 9.5 12.8 10.9 Lubricating oil 70.9 88.2 84.7 86.9 Coating agent 4.9 2.3 2.5 2.2 Test Data Penetration unworked 271 344 335 301 (ASTMDZl7-60l) Worked strokes 321 327 342 325 Worked 100,000 strokes 250 342 404 377 Dropping point, F. (ASTM D-2265-64T) 625+ 587 605 625+ Shell roll, (ST-230-61) Points change +5 -20 +6 +1 1 Water absorption, (SP-344-60) 60 8O 6O Penetration before Composititon, parts by weight:

Palmitie acid p-(N-lauroyl) aminobenzo acid Mineral oil pha-naphthylamme Penetration (ASTM D217-601):

Phenyl- T st Unworked Worked 60 strokes Worked 100,000 strokes Dropping pt., F. (ASTM 2265-641) Shell roll (ST-230451) poiiugslfhangeflu Water absorption (SP-34 Penetration before Penetration emu1sion Wager washout at Tlmken breakdown ASTM bomb oxidation:

100 hrs 7 500 hrs 8 TAB LE III Greases similar to Typical grease Grease containing those disclosed in composition of uncoated abestos U.S.P. 3,433,743 this invention,

12a 12b 12c 12d 12e As the specification including the examples indicate, the novel greases of this invention are advantageous in several respects. For example, the thickened fibrous greases particularly the asbestos thickened grease are economical to prepare, and produce greases having superior E.P., shear resistance and water resistance. In addition, the novel thickening systems are particularly advantageous where synthetic oils are employed as the lubricating oil base. Surprising enough, greases thickened with the coating agents disclosed herein are superior to greases disclosed in U.S. Pat. No. 3,433,743 which employs aliphatic carboxylic acids as the coating agents.

As indicated above, numerous changes, modifications and substitutions in fibrous material, lubricating oils and coating agents may be made without departing from the inventive concept. The metes and bounds of this invention are best gleaned by the claims which follow, read in conjunction with the patent specification.

What is claimed is:

1. A grease composition having superior shear stability, water-resistance and extreme pressure properties, comprising from about 65 to 96 weight percent of lubricating oil including adjuvants, from about 25 to 3.5 weight percent of fibrous asbestos grease thickener and about 10 to 0.5 weight percent of aromatic coating agents included within the structure:

H O LLB wherein R is an aliphatic radical containing up to 30 carbon atoms and R is an aliphatic radical containing up to 30 carbon atoms.

2. The grease composition of claim 1 wherein the lubricating oil is a mineral.

3. The grease composition of claim 1 wherein the lubricating oil is a synthetic oil.

4. The grease composition of claim 1 wherein the asbestos is colloidal in size.

5. The grease composition of claim 1 wherein the asbestos is non-colloidal in size.

6. The grease composition of claim 1 wherein the aromatic coating agent is the methyl ester of p-(N- octadecoyl) aminobenzoic acid.

, UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Y Patent No. 3,773,663 Dated C November 20,- 1975 I nventofls) EDWARD A. CROSS, ET. AL.

Itis certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5-, line 51, "0.70" should read .70

Column 8, the. formula at Example 5 reading Column 8, the formula. at Example 5 reading Ca. 00c{ -%1r1coc 1 should read Ca(00C--NHCOC H 1 Signed and' Sealed this 6th day of August 1974.

(SEAL) Attest: 1

MCCOY GIBSON JR. C. MARSHALL DANN Attestlng Officer Commissioner of Patents 

2. The grease composition of claim 1 wherein the lubricating oil is a mineral.
 3. The grease composition of claim 1 wherein the lubricating oil is a synthetic oil.
 4. The grease composition of claim 1 wherein the asbestos is colloidal in size.
 5. The grease composition of claim 1 wherein the asbestos is non-colloidal in size.
 6. The grease composition of claim 1 wherein the aromatic coating agent is the methyl ester of p-(N-octadecoyl) aminobenzoic acid. 